Conventionally, signal quality between a base transceiver station and a mobile unit may degrade under certain conditions. For example, when a user moves from an outside location to an indoor location (e.g., a building), wireless signal strength may degrade significantly because radio signals must pass through or around various obstructions (e.g., walls, ceilings, etc.). U.S. patent application Ser. Nos. 10/884,203 to Feder et al. and 11/435,665 to Wijngaarden et al. discuss methods and apparatuses for introducing cellular or other wireless signals/messages into a building or other location by transmitting data packets corresponding to those signals over a high-speed data network.
FIG. 1 shows a conventional in-building communications network such as those described in U.S. patent application Ser. Nos. 10/884,203 and 11/435,665. In the network of FIG. 1, the base station interfaces (BSIs) 12A, 14B, radio distributor/aggregator (RDA) 110, remote radio heads (RRHs) 111-115 and a plurality of mobile units (including mobile unit 119) may be located in a building. A base transceiver station (BTS) 100 may be geographically separated from these in-building network components.
Referring to FIG. 1, in the downlink (e.g., from BTS 10 to mobile unit 119) wireless signals are received at BSI 12A from the BTS 10. The BSI 12A processes the wireless signals to generate a mobile user-coded baseband signal (hereinafter a data signal) and stores the generated data signal in a buffer (not shown). Once the buffer reaches a given threshold level, or a given amount of time has passed, the BSI 12A packetizes (e.g., into one or more Ethernet packets) the data signal to generate data packets (or data packet stream) including a destination address (e.g., a MAC address) corresponding to one or more RRHs (e.g., RRHs 111-113 corresponding to sector A). The BSI 12A forwards the data packets over a high-speed data network, such as a gigabit Ethernet network, to the RDA 110.
As is well-known, the RDA 110 serves as a network switch having a plurality of ports. Each port on the RDA 110 may correspond to one or more addressable sectors for routing data packets between BSIs 12A and 14B and RRHs 111-115. One or more RRHs may belong to a particular sector. With regard to FIG. 1, for example, RRHs 111-113 belong to sector A, whereas RRHs 114 and 115 belong to sector B. Each RRH corresponds to and provides an area of wireless coverage within a building.
Still referring to FIG. 1, the RDA 110 receives the data packets from the BSI 12A having addresses corresponding to sector A and identifies which ports on the RDA 110 are associated with RRHs in sector A. In one example, the RDA 110 identifies these ports by comparing the received addresses with entries in a look-up table. This well-known look-up procedure may use a variety of existing Ethernet protocols, such as using special multicast addresses, or having all RRHs belonging to a particular sector be a part of the same virtual LAN (VLAN), and broadcasting packets on that VLAN.
Once the RDA 110 has identified the ports corresponding to sector A, the RDA 110 replicates the data packets (if necessary) and forwards a copy of each data packet to the appropriate RRHs 111-113. In this example, the RDA 110 replicates and sends the received data packets to RRHs 111-113 serving mobile unit 119.
As is well-known, each RRH 111-115 includes network interface equipment, timing and frequency synchronization equipment, signal processing elements, a power amplifier and one or more antennas. The network interface equipment of the destination RRH (e.g., RRHs 111-113) receives and buffers the data packets from the RDA 110, removes the packet header and processes the data packets to recover the data signal.
The data signal is buffered, processed, converted to RF signals, amplified and broadcast over the air via the antenna(s) as is well-known in the art.
Still referring to FIG. 1, in the uplink, mobile units in sector A transmit wireless signals to RRHs 111-113. Each of RRHs 111-113 process the received wireless signals in the same manner as the BSI 12A processes the downlink wireless signals to generate data signals. Each of the RRHs 111-113 also buffers and then packetizes the generated data signals in the same manner as at the BSI 12A to generate a plurality of data packets. The RRHs 111-113 transmit the uplink data packets to the RDA 110 via the high-speed data network.
The RDA 110 buffers and processes the data packets to recover the uplink data signals and combines the data signals from each of RRHs 111-113 to generate a resultant uplink data signal. The resultant uplink data signal is re-packetized and forwarded to BSI 12A.
The BSI 12A processes the received data packets to recover the resultant uplink data signal and further processes the data signal to generate wireless signals for transmission to the BTS 10.
As discussed above, RRHs may be grouped into sectors. The RRHs within each sector may simulcast the same downlink signal, and the uplink signals received from each RRH may be combined together to form a single uplink signal for transmission to BTS 10. Conventionally, sectors within a building may be changed using software configurations. In certain situations, it may be desirable to dynamically change the coverage of different sectors to match the changing user traffic density.
For example, when a hot spot develops over a certain area covered by a group of RRHs belonging to a single sector, some of the RRHs in the group may be reconfigured to join another sector to shed the traffic load into that sector. However, if the reconfiguration is performed suddenly, the users served by the RRHs switching sectors, may experience disruption in service.